Re: [dpdk-dev] [PATCH v2 5/7] net/mlx5: e-switch VXLAN tunnel devices management

[Slava Ovsiienko <viacheslavo@mellanox.com>]

> -----Original Message-----
> From: Yongseok Koh
> Sent: Saturday, October 27, 2018 1:43
> To: Slava Ovsiienko <viacheslavo@mellanox.com>
> Cc: Shahaf Shuler <shahafs@mellanox.com>; dev@dpdk.org
> Subject: Re: [PATCH v2 5/7] net/mlx5: e-switch VXLAN tunnel devices
> management
> 
> On Fri, Oct 26, 2018 at 02:35:24AM -0700, Slava Ovsiienko wrote:
> > > -----Original Message-----
> > > From: Yongseok Koh
> > > Sent: Friday, October 26, 2018 9:26
> > > To: Slava Ovsiienko <viacheslavo@mellanox.com>
> > > Cc: Shahaf Shuler <shahafs@mellanox.com>; dev@dpdk.org
> > > Subject: Re: [PATCH v2 5/7] net/mlx5: e-switch VXLAN tunnel devices
> > > management
> > >
> > > On Thu, Oct 25, 2018 at 01:21:12PM -0700, Slava Ovsiienko wrote:
> > > > > -----Original Message-----
> > > > > From: Yongseok Koh
> > > > > Sent: Thursday, October 25, 2018 3:28
> > > > > To: Slava Ovsiienko <viacheslavo@mellanox.com>
> > > > > Cc: Shahaf Shuler <shahafs@mellanox.com>; dev@dpdk.org
> > > > > Subject: Re: [PATCH v2 5/7] net/mlx5: e-switch VXLAN tunnel
> > > > > devices management
> > > > >
> > > > > On Mon, Oct 15, 2018 at 02:13:33PM +0000, Viacheslav Ovsiienko
> wrote:
> > > > > > VXLAN interfaces are dynamically created for each local UDP
> > > > > > port of outer networks and then used as targets for TC
> > > > > > "flower" filters in order to perform encapsulation. These
> > > > > > VXLAN interfaces are system-wide, the only one device with
> > > > > > given UDP port can exist in the system (the attempt of
> > > > > > creating another device with the same UDP local port returns
> > > > > > EEXIST), so PMD should support the shared device instances
> > > > > > database for PMD instances. These VXLAN implicitly created devices
> are called VTEPs (Virtual Tunnel End Points).
> > > > > >
> > > > > > Creation of the VTEP occurs at the moment of rule applying.
> > > > > > The link is set up, root ingress qdisc is also initialized.
> > > > > >
> > > > > > Encapsulation VTEPs are created on per port basis, the single
> > > > > > VTEP is attached to the outer interface and is shared for all
> > > > > > encapsulation rules on this interface. The source UDP port is
> > > > > > automatically selected in range 30000-60000.
> > > > > >
> > > > > > For decapsulaton one VTEP is created per every unique UDP
> > > > > > local port to accept tunnel traffic. The name of created VTEP
> > > > > > consists of prefix "vmlx_" and the number of UDP port in
> > > > > > decimal digits without leading zeros (vmlx_4789). The VTEP can
> > > > > > be preliminary created in the system before the launching
> > > > > > application, it allows to share	UDP ports between primary
> > > > > > and secondary processes.
> > > > > >
> > > > > > Suggested-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
> > > > > > Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
> > > > > > ---
> > > > > >  drivers/net/mlx5/mlx5_flow_tcf.c | 503
> > > > > > ++++++++++++++++++++++++++++++++++++++-
> > > > > >  1 file changed, 499 insertions(+), 4 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/net/mlx5/mlx5_flow_tcf.c
> > > > > > b/drivers/net/mlx5/mlx5_flow_tcf.c
> > > > > > index d6840d5..efa9c3b 100644
> > > > > > --- a/drivers/net/mlx5/mlx5_flow_tcf.c
> > > > > > +++ b/drivers/net/mlx5/mlx5_flow_tcf.c
> > > > > > @@ -3443,6 +3443,432 @@ struct pedit_parser {
> > > > > >  	return -err;
> > > > > >  }
> > > > > >
> > > > > > +/* VTEP device list is shared between PMD port instances. */
> > > > > > +static LIST_HEAD(, mlx5_flow_tcf_vtep)
> > > > > > +			vtep_list_vxlan = LIST_HEAD_INITIALIZER();
> static
> > > > > pthread_mutex_t
> > > > > > +vtep_list_mutex = PTHREAD_MUTEX_INITIALIZER;
> > > > >
> > > > > What's the reason for choosing pthread_mutex instead of
> rte_*_lock?
> > > >
> > > > The sharing this database for secondary processes?
> > >
> > > The static variable isn't shared with sec proc. But you can leave it as is.
> >
> > Yes. The sharing just was assumed, not implemented yet.
> >
> > >
> > > > > > +
> > > > > > +/**
> > > > > > + * Deletes VTEP network device.
> > > > > > + *
> > > > > > + * @param[in] tcf
> > > > > > + *   Context object initialized by mlx5_flow_tcf_context_create().
> > > > > > + * @param[in] vtep
> > > > > > + *   Object represinting the network device to delete. Memory
> > > > > > + *   allocated for this object is freed by routine.
> > > > > > + */
> > > > > > +static void
> > > > > > +flow_tcf_delete_iface(struct mlx6_flow_tcf_context *tcf,
> > > > > > +		      struct mlx5_flow_tcf_vtep *vtep) {
> > > > > > +	struct nlmsghdr *nlh;
> > > > > > +	struct ifinfomsg *ifm;
> > > > > > +	alignas(struct nlmsghdr)
> > > > > > +	uint8_t buf[mnl_nlmsg_size(MNL_ALIGN(sizeof(*ifm))) + 8];
> > > > > > +	int ret;
> > > > > > +
> > > > > > +	assert(!vtep->refcnt);
> > > > > > +	if (vtep->created && vtep->ifindex) {
> > > > >
> > > > > First of all vtep->created seems of no use. It is introduced to
> > > > > select the error message in flow_tcf_create_iface(). I don't see
> > > > > any necessity to distinguish between 'vtep is allocated by
> > > > > rte_malloc()' and
> > > 'vtep is created in kernel'.
> > > >
> > > > created flag indicates the iface is created by our code.
> > > > The VXLAN decap devices must have the specified UDP port, we can
> > > > not create multiple VXLAN devices with the same UDP port - EEXIST
> > > > is returned. So, we have to share device. One option is create
> > > > device before DPDK application launch and use these pre-created
> devices.
> > > > Inthis case created flag is not set and VXLAN device is not
> > > > reinitialized, and
> > > not deleted.
> > >
> > > I can't see any code to use pre-created device (created even before
> > > dpdk app launch). Your code just tries to create 'vmlx_xxxx'. Even
> > > from your comment in [7/7] patch, PMD will cleanup any leftovers
> > > (existing vtep devices) on initialization. Your comment sounds conflicting
> and confusing.
> >
> > There are two types of VXLAN devices:
> >
> > - VXLAN decap, not attached to any ifouter. Provides the ingress UDP
> > port,  we try to share the devices of this type, because we may be
> > asked for  the specified UDP port. No device/rule cleanup and reinit
> needed.
> >
> > - VXLAN encap, should be attached to ifouter to provide strict egress
> > path, no need to share - egress UDP port does not matter. And we need
> > to cleanup ifouter, remove other attached VXLAN devices and rules,
> > because it is too hard to co-exist with some pre-created setup..
> 
> I knew that. But how can it justify the need of 'created' field in vtep struct?
> In this code, it is of no use. But will see how it is used in your v3.
> 
> > > > > And why do you need to check vtep->ifindex as well? If vtep is
> > > > > created in kernel and its ifindex isn't set, that should be an
> > > > > error which had to be hanled in flow_tcf_create_iface(). Such a
> > > > > vtep shouldn't
> > > exist.
> > > > Yes, if we did not get ifindex of device - vtep is not created, error
> returned.
> > > > We just can not operate w/o ifindex.
> > >
> > > I know ifindex is needed but my question was checking vtep->ifindex
> > > here looked redundant/unnecessary. But as you agreed on having
> > > create/get/release_iface(), it doesn't matter much.
> >
> > Yes. I agree, will refactor the code.
> >
> > >
> > > > > Also, the refcnt management is a bit strange. Please put an
> > > > > abstraction by adding create_iface(), get_iface() and
> > > > > release_iface(). In the get_ifce(),
> > > > > vtep->refcnt should be incremented. And in the release_iface(),
> > > > > vtep->it decrease the
> > > > OK. Good proposal. I'll refactor the code.
> > > >
> > > > > refcnt and if it reaches to zero, the iface can be removed.
> > > > > create_iface() will set the refcnt to 1. And if you refer to
> > > > > mlx5_hrxq_get(), it even does searching the list not by
> > > > > repeating the
> > > same lookup code here and there.
> > > > > That will make your code much simpler.
> > > > >
> > > > > > +		DRV_LOG(INFO, "VTEP delete (%d)", vtep->ifindex);
> > > > > > +		nlh = mnl_nlmsg_put_header(buf);
> > > > > > +		nlh->nlmsg_type = RTM_DELLINK;
> > > > > > +		nlh->nlmsg_flags = NLM_F_REQUEST;
> > > > > > +		ifm = mnl_nlmsg_put_extra_header(nlh,
> sizeof(*ifm));
> > > > > > +		ifm->ifi_family = AF_UNSPEC;
> > > > > > +		ifm->ifi_index = vtep->ifindex;
> > > > > > +		ret = flow_tcf_nl_ack(tcf, nlh, 0, NULL, NULL);
> > > > > > +		if (ret)
> > > > > > +			DRV_LOG(WARNING, "netlink: error deleting
> VXLAN
> > > > > "
> > > > > > +					 "encap/decap ifindex %u",
> > > > > > +					 ifm->ifi_index);
> > > > > > +	}
> > > > > > +	rte_free(vtep);
> > > > > > +}
> > > > > > +
> > > > > > +/**
> > > > > > + * Creates VTEP network device.
> > > > > > + *
> > > > > > + * @param[in] tcf
> > > > > > + *   Context object initialized by mlx5_flow_tcf_context_create().
> > > > > > + * @param[in] ifouter
> > > > > > + *   Outer interface to attach new-created VXLAN device
> > > > > > + *   If zero the VXLAN device will not be attached to any device.
> > > > > > + * @param[in] port
> > > > > > + *   UDP port of created VTEP device.
> > > > > > + * @param[out] error
> > > > > > + *   Perform verbose error reporting if not NULL.
> > > > > > + *
> > > > > > + * @return
> > > > > > + * Pointer to created device structure on success, NULL
> > > > > > +otherwise
> > > > > > + * and rte_errno is set.
> > > > > > + */
> > > > > > +#ifndef HAVE_IFLA_VXLAN_COLLECT_METADATA
> > > > >
> > > > > Why negative(ifndef) first intead of positive(ifdef)?
> > > > Hm. Did I miss the rule. Positive #ifdef first? OK.
> > >
> > > No concrete rule but if there's no specific reason, it would be
> > > better to start from ifdef.
> > >
> > > > > > +static struct mlx5_flow_tcf_vtep*
> > > > > > +flow_tcf_create_iface(struct mlx5_flow_tcf_context *tcf
> __rte_unused,
> > > > > > +		      unsigned int ifouter __rte_unused,
> > > > > > +		      uint16_t port __rte_unused,
> > > > > > +		      struct rte_flow_error *error) {
> > > > > > +	rte_flow_error_set(error, ENOTSUP,
> > > > > > +			 RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
> NULL,
> > > > > > +			 "netlink: failed to create VTEP, "
> > > > > > +			 "VXLAN metadat is not supported by
> kernel");
> > > > >
> > > > > Typo.
> > > >
> > > > OK.  "metadata are not supported".
> > > > >
> > > > > > +	return NULL;
> > > > > > +}
> > > > > > +#else
> > > > > > +static struct mlx5_flow_tcf_vtep*
> > > > > > +flow_tcf_create_iface(struct mlx5_flow_tcf_context *tcf,
> > > > >
> > > > > How about adding 'vtep'? It sounds vague - creating a general
> interface.
> > > > > E.g., flow_tcf_create_vtep_iface()?
> > > >
> > > > OK.
> > > >
> > > > >
> > > > > > +		      unsigned int ifouter,
> > > > > > +		      uint16_t port, struct rte_flow_error *error) {
> > > > > > +	struct mlx5_flow_tcf_vtep *vtep;
> > > > > > +	struct nlmsghdr *nlh;
> > > > > > +	struct ifinfomsg *ifm;
> > > > > > +	char name[sizeof(MLX5_VXLAN_DEVICE_PFX) + 24];
> > > > > > +	alignas(struct nlmsghdr)
> > > > > > +	uint8_t buf[mnl_nlmsg_size(sizeof(*ifm)) + 128 +
> > > > >
> > > > > Use a macro for '128'. Can't know the meaning.
> > > > OK. I think we should calculate the buffer size explicitly.
> > > >
> > > > >
> > > > > > +		       SZ_NLATTR_DATA_OF(sizeof(name)) +
> > > > > > +		       SZ_NLATTR_NEST * 2 +
> > > > > > +		       SZ_NLATTR_STRZ_OF("vxlan") +
> > > > > > +		       SZ_NLATTR_DATA_OF(sizeof(uint32_t)) +
> > > > > > +		       SZ_NLATTR_DATA_OF(sizeof(uint32_t)) +
> > > > > > +		       SZ_NLATTR_DATA_OF(sizeof(uint16_t)) +
> > > > > > +		       SZ_NLATTR_DATA_OF(sizeof(uint8_t))];
> > > > > > +	struct nlattr *na_info;
> > > > > > +	struct nlattr *na_vxlan;
> > > > > > +	rte_be16_t vxlan_port = RTE_BE16(port);
> > > > >
> > > > > Use rte_cpu_to_be_*() instead.
> > > >
> > > > Yes, I'll recheck the whole code for this issue.
> > > >
> > > > >
> > > > > > +	int ret;
> > > > > > +
> > > > > > +	vtep = rte_zmalloc(__func__, sizeof(*vtep),
> > > > > > +			alignof(struct mlx5_flow_tcf_vtep));
> > > > > > +	if (!vtep) {
> > > > > > +		rte_flow_error_set
> > > > > > +			(error, ENOMEM,
> > > > > RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
> > > > > > +			 NULL, "unadble to allocate memory for
> VTEP desc");
> > > > > > +		return NULL;
> > > > > > +	}
> > > > > > +	*vtep = (struct mlx5_flow_tcf_vtep){
> > > > > > +			.refcnt = 0,
> > > > > > +			.port = port,
> > > > > > +			.created = 0,
> > > > > > +			.ifouter = 0,
> > > > > > +			.ifindex = 0,
> > > > > > +			.local = LIST_HEAD_INITIALIZER(),
> > > > > > +			.neigh = LIST_HEAD_INITIALIZER(),
> > > > > > +	};
> > > > > > +	memset(buf, 0, sizeof(buf));
> > > > > > +	nlh = mnl_nlmsg_put_header(buf);
> > > > > > +	nlh->nlmsg_type = RTM_NEWLINK;
> > > > > > +	nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE  |
> > > > > NLM_F_EXCL;
> > > > > > +	ifm = mnl_nlmsg_put_extra_header(nlh, sizeof(*ifm));
> > > > > > +	ifm->ifi_family = AF_UNSPEC;
> > > > > > +	ifm->ifi_type = 0;
> > > > > > +	ifm->ifi_index = 0;
> > > > > > +	ifm->ifi_flags = IFF_UP;
> > > > > > +	ifm->ifi_change = 0xffffffff;
> > > > > > +	snprintf(name, sizeof(name), "%s%u",
> MLX5_VXLAN_DEVICE_PFX,
> > > > > port);
> > > > > > +	mnl_attr_put_strz(nlh, IFLA_IFNAME, name);
> > > > > > +	na_info = mnl_attr_nest_start(nlh, IFLA_LINKINFO);
> > > > > > +	assert(na_info);
> > > > > > +	mnl_attr_put_strz(nlh, IFLA_INFO_KIND, "vxlan");
> > > > > > +	na_vxlan = mnl_attr_nest_start(nlh, IFLA_INFO_DATA);
> > > > > > +	if (ifouter)
> > > > > > +		mnl_attr_put_u32(nlh, IFLA_VXLAN_LINK, ifouter);
> > > > > > +	assert(na_vxlan);
> > > > > > +	mnl_attr_put_u8(nlh, IFLA_VXLAN_COLLECT_METADATA, 1);
> > > > > > +	mnl_attr_put_u8(nlh, IFLA_VXLAN_UDP_ZERO_CSUM6_RX,
> 1);
> > > > > > +	mnl_attr_put_u8(nlh, IFLA_VXLAN_LEARNING, 0);
> > > > > > +	mnl_attr_put_u16(nlh, IFLA_VXLAN_PORT, vxlan_port);
> > > > > > +	mnl_attr_nest_end(nlh, na_vxlan);
> > > > > > +	mnl_attr_nest_end(nlh, na_info);
> > > > > > +	assert(sizeof(buf) >= nlh->nlmsg_len);
> > > > > > +	ret = flow_tcf_nl_ack(tcf, nlh, 0, NULL, NULL);
> > > > > > +	if (ret)
> > > > > > +		DRV_LOG(WARNING,
> > > > > > +			"netlink: VTEP %s create failure (%d)",
> > > > > > +			name, rte_errno);
> > > > > > +	else
> > > > > > +		vtep->created = 1;
> > > > >
> > > > > Flow of code here isn't smooth, thus could be error-prone. Most
> > > > > of all, I don't like ret has multiple meanings. ret should be
> > > > > return value but you are using it to store ifindex.
> > > > >
> > > > > > +	if (ret && ifouter)
> > > > > > +		ret = 0;
> > > > > > +	else
> > > > > > +		ret = if_nametoindex(name);
> > > > >
> > > > > If vtep isn't created and ifouter is set, then skip init below,
> > > > > which means, if
> > > >
> > > > ifouter is set for VXLAN encap devices. They should be attached to
> > > > ifouter and can not be shared. So, if ifouter I set - we do not
> > > > use the precreated/existing VXLAN devices. We have to create our
> > > > own not
> > > shared device.
> > >
> > > In your code (flow_tcf_encap_vtep_create()), it is shared by multiple
> flows.
> > > Do you mean it isn't shared between different outer ifaces? If so,
> > > that's for sure.
> > Sorry, I do not understand the question.
> > VXLAN encap device is attached to ifouter and shared by all flows with
> > this ifouter. No multiple VXLAN devices are attached to the same ifouter,
> only one.
> > VXLAN decap device has no attached ifouter, so it can not share it.
> 
> Yep, that's what I meant.
> 
> > > > > vtep is created or ifouter is set, it tries to get ifindex of vtep.
> > > > > But why do you want to try to call this API even if it failed to create
> vtep?
> > > > > Let's not make code flow convoluted even though it logically works.
> > > > > Let's make it straightforward.
> > > > >
> > > > > > +	if (ret) {
> > > > > > +		vtep->ifindex = ret;
> > > > > > +		vtep->ifouter = ifouter;
> > > > > > +		memset(buf, 0, sizeof(buf));
> > > > > > +		nlh = mnl_nlmsg_put_header(buf);
> > > > > > +		nlh->nlmsg_type = RTM_NEWLINK;
> > > > > > +		nlh->nlmsg_flags = NLM_F_REQUEST;
> > > > > > +		ifm = mnl_nlmsg_put_extra_header(nlh,
> sizeof(*ifm));
> > > > > > +		ifm->ifi_family = AF_UNSPEC;
> > > > > > +		ifm->ifi_type = 0;
> > > > > > +		ifm->ifi_index = vtep->ifindex;
> > > > > > +		ifm->ifi_flags = IFF_UP;
> > > > > > +		ifm->ifi_change = IFF_UP;
> > > > > > +		ret = flow_tcf_nl_ack(tcf, nlh, 0, NULL, NULL);
> > > > > > +		if (ret) {
> > > > > > +			DRV_LOG(WARNING,
> > > > > > +				"netlink: VTEP %s set link up failure
> (%d)",
> > > > > > +				name, rte_errno);
> > > > > > +			rte_free(vtep);
> > > > > > +			rte_flow_error_set
> > > > > > +				(error, -errno,
> > > > > > +
> RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
> > > > > NULL,
> > > > > > +				 "netlink: failed to set VTEP link up");
> > > > > > +			vtep = NULL;
> > > > > > +		} else {
> > > > > > +			ret = mlx5_flow_tcf_init(tcf, vtep->ifindex,
> error);
> > > > > > +			if (ret)
> > > > > > +				DRV_LOG(WARNING,
> > > > > > +				"VTEP %s init failure (%d)", name,
> rte_errno);
> > > > > > +		}
> > > > > > +	} else {
> > > > > > +		DRV_LOG(WARNING,
> > > > > > +			"VTEP %s failed to get index (%d)", name,
> errno);
> > > > > > +		rte_flow_error_set
> > > > > > +			(error, -errno,
> > > > > > +			 RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
> NULL,
> > > > > > +			 !vtep->created ? "netlink: failed to create
> VTEP" :
> > > > > > +			 "netlink: failed to retrieve VTEP ifindex");
> > > > > > +			 ret = 1;
> > > > >
> > > > > If it fails to create a vtep above, it will print out two
> > > > > warning messages and one rte_flow_error message. And it even
> > > > > selects message to print between two?
> > > > > And there's another info msg at the end even in case of failure.
> > > > > Do you really want to do this even with manipulating ret to
> > > > > change code path?  Not a good practice.
> > > > >
> > > > > Usually, code path should be straightforward for sucessful path
> > > > > and for errors/failures, return immediately or use 'goto' if
> > > > > there's need for
> > > cleanup.
> > > > >
> > > > > Please refactor entire function.
> > > >
> > > > I think I'll split it in two ones - for attached and potentially shared
> ifaces.
> > > > >
> > > > > > +	}
> > > > > > +	if (ret) {
> > > > > > +		flow_tcf_delete_iface(tcf, vtep);
> > > > > > +		vtep = NULL;
> > > > > > +	}
> > > > > > +	DRV_LOG(INFO, "VTEP create (%d, %s)", vtep->port, vtep ?
> "OK" :
> > > > > "error");
> > > > > > +	return vtep;
> > > > > > +}
> > > > > > +#endif /* HAVE_IFLA_VXLAN_COLLECT_METADATA */
> > > > > > +
> > > > > > +/**
> > > > > > + * Create target interface index for VXLAN tunneling
> decapsulation.
> > > > > > + * In order to share the UDP port within the other interfaces
> > > > > > +the
> > > > > > + * VXLAN device created as not attached to any interface (if
> created).
> > > > > > + *
> > > > > > + * @param[in] tcf
> > > > > > + *   Context object initialized by mlx5_flow_tcf_context_create().
> > > > > > + * @param[in] dev_flow
> > > > > > + *   Flow tcf object with tunnel structure pointer set.
> > > > > > + * @param[out] error
> > > > > > + *   Perform verbose error reporting if not NULL.
> > > > > > + * @return
> > > > > > + *   Interface index on success, zero otherwise and rte_errno is set.
> > > > >
> > > > > Return negative errno in case of failure like others.
> > > >
> > > > Anyway, we have to return an index. If we do not return it as
> > > > function result we will need to provide some extra pointing
> > > > parameter, it
> > > complicates the code.
> > >
> > > You misunderstood it. See what I wrote below. The function still
> > > returns the index but in case of error, make it return negative errno
> instead of zero.
> > >
> > > > >
> > > > >  *   Interface index on success, a negative errno value otherwise and
> > > > > rte_errno is set.
> > > > >
> > > > > > + */
> > > > > > +static unsigned int
> > > > > > +flow_tcf_decap_vtep_create(struct mlx5_flow_tcf_context *tcf,
> > > > > > +			   struct mlx5_flow *dev_flow,
> > > > > > +			   struct rte_flow_error *error) {
> > > > > > +	struct mlx5_flow_tcf_vtep *vtep, *vlst;
> > > > > > +	uint16_t port = dev_flow->tcf.vxlan_decap->udp_port;
> > > > > > +
> > > > > > +	vtep = NULL;
> > > > > > +	LIST_FOREACH(vlst, &vtep_list_vxlan, next) {
> > > > > > +		if (vlst->port == port) {
> > > > > > +			vtep = vlst;
> > > > > > +			break;
> > > > > > +		}
> > > > > > +	}
> > > > >
> > > > > You just need one variable.
> > > >
> > > > Yes. There is a long story, I forgot to revert code to one
> > > > variable after
> > > debugging.
> > > > >
> > > > > 	struct mlx5_flow_tcf_vtep *vtep;
> > > > >
> > > > > 	LIST_FOREACH(vtep, &vtep_list_vxlan, next) {
> > > > > 		if (vtep->port == port)
> > > > > 			break;
> > > > > 	}
> > > > >
> > > > > > +	if (!vtep) {
> > > > > > +		vtep = flow_tcf_create_iface(tcf, 0, port, error);
> > > > > > +		if (vtep)
> > > > > > +			LIST_INSERT_HEAD(&vtep_list_vxlan, vtep,
> next);
> > > > > > +	} else {
> > > > > > +		if (vtep->ifouter) {
> > > > > > +			rte_flow_error_set(error, -errno,
> > > > > > +
> 	RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
> > > > > NULL,
> > > > > > +				"Failed to create decap VTEP,
> attached "
> > > > > > +				"device with the same UDP port
> exists");
> > > > > > +				vtep = NULL;
> > > > >
> > > > > Making vtep null to skip the following code?
> > > >
> > > > Yes. To avoid multiple return operators in code.
> > >
> > > It's okay to have multiple returns. Why not?
> >
> > It is easy to miss the return in the midst of function  while
> refactoring/modifying the code.
> 
> Your code path doesn't look easy and free from error. Please refer to other
> control path functions in this PMD.
> 
> > > > > Please merge the two same
> > > > > if/else and make the code path strightforward. And which errno
> > > > > do you expect here?
> > > > > Should it be set EEXIST instead?
> > > > Not always. Netlink returns the code.
> > >
> > > No, that's not my point. Your code above sets errno instead of
> > > rte_errno or EEXIST.
> > >
> > > 	} else {
> > > 		if (vtep->ifouter) {
> > > 			rte_flow_error_set(error, -errno,
> > >
> > > Which one sets this errno? Here, it sets rte_errno because matched
> > > vtep
> > libmnl sets, while processing the Netlink reply message (callback.c of libmnl
> sources).
> 
> You still don't understand my point.
> 
> In this flow_tcf_decap_vtep_create(), if vtep is found (vtep != NULL), how
> can errno be set? Before the if/else, there's no libmnl call.
> 
> > > can't be used as it already has outer iface attached (error message
> > > isn't clear, please reword it too). I thought this should be EEXIST
> > > but you set errno to rte_errno but errno isn't valid at this point.
> > >
> > > >
> > > > >
> > > > > > +		}
> > > > > > +	}
> > > > > > +	if (vtep) {
> > > > > > +		vtep->refcnt++;
> > > > > > +		assert(vtep->ifindex);
> > > > > > +		return vtep->ifindex;
> > > > > > +	} else {
> > > > > > +		return 0;
> > > > > > +	}
> > > > >
> > > > > Why repeating same if/else?
> > > > >
> > > > >
> > > > > This is my suggestion but if you take my suggestion to have
> > > > > flow_tcf_[create|get|release]_iface(), this will get much simpler.
> > > > Agree.
> > > >
> > > > >
> > > > > {
> > > > > 	struct mlx5_flow_tcf_vtep *vtep;
> > > > > 	uint16_t port = dev_flow->tcf.vxlan_decap->udp_port;
> > > > >
> > > > > 	LIST_FOREACH(vtep, &vtep_list_vxlan, next) {
> > > > > 		if (vtep->port == port)
> > > > > 			break;
> > > > > 	}
> > > > > 	if (vtep && vtep->ifouter)
> > > > > 		return rte_flow_error_set(... EEXIST ...);
> > > > > 	else if (vtep) {
> > > > > 		++vtep->refcnt;
> > > > > 	} else {
> > > > > 		vtep = flow_tcf_create_iface(tcf, 0, port, error);
> > > > > 		if (!vtep)
> > > > > 			return rte_flow_error_set(...);
> > > > > 		LIST_INSERT_HEAD(&vtep_list_vxlan, vtep, next);
> > > > > 	}
> > > > > 	assert(vtep->ifindex);
> > > > > 	return vtep->ifindex;
> > > > > }
> > > > >
> > > > >
> > > > > > +}
> > > > > > +
> > > > > > +/**
> > > > > > + * Creates target interface index for VXLAN tunneling
> encapsulation.
> > > > > > + *
> > > > > > + * @param[in] tcf
> > > > > > + *   Context object initialized by mlx5_flow_tcf_context_create().
> > > > > > + * @param[in] ifouter
> > > > > > + *   Network interface index to attach VXLAN encap device to.
> > > > > > + * @param[in] dev_flow
> > > > > > + *   Flow tcf object with tunnel structure pointer set.
> > > > > > + * @param[out] error
> > > > > > + *   Perform verbose error reporting if not NULL.
> > > > > > + * @return
> > > > > > + *   Interface index on success, zero otherwise and rte_errno is set.
> > > > > > + */
> > > > > > +static unsigned int
> > > > > > +flow_tcf_encap_vtep_create(struct mlx5_flow_tcf_context *tcf,
> > > > > > +			    unsigned int ifouter,
> > > > > > +			    struct mlx5_flow *dev_flow __rte_unused,
> > > > > > +			    struct rte_flow_error *error) {
> > > > > > +	static uint16_t encap_port =
> MLX5_VXLAN_PORT_RANGE_MIN - 1;
> > > > > > +	struct mlx5_flow_tcf_vtep *vtep, *vlst;
> > > > > > +
> > > > > > +	assert(ifouter);
> > > > > > +	/* Look whether the attached VTEP for encap is created. */
> > > > > > +	vtep = NULL;
> > > > > > +	LIST_FOREACH(vlst, &vtep_list_vxlan, next) {
> > > > > > +		if (vlst->ifouter == ifouter) {
> > > > > > +			vtep = vlst;
> > > > > > +			break;
> > > > > > +		}
> > > > > > +	}
> > > > >
> > > > > Same here.
> > > > >
> > > > > > +	if (!vtep) {
> > > > > > +		uint16_t pcnt;
> > > > > > +
> > > > > > +		/* Not found, we should create the new attached
> VTEP. */
> > > > > > +/*
> > > > > > + * TODO: not implemented yet
> > > > > > + * flow_tcf_encap_iface_cleanup(tcf, ifouter);
> > > > > > + * flow_tcf_encap_local_cleanup(tcf, ifouter);
> > > > > > + * flow_tcf_encap_neigh_cleanup(tcf, ifouter);  */
> > > > >
> > > > > Personal note is not appropriate even though it is removed in
> > > > > the following patch.
> > > > >
> > > > > > +		for (pcnt = 0; pcnt <=
> (MLX5_VXLAN_PORT_RANGE_MAX
> > > > > > +				     -
> MLX5_VXLAN_PORT_RANGE_MIN);
> > > > > pcnt++) {
> > > > > > +			encap_port++;
> > > > > > +			/* Wraparound the UDP port index. */
> > > > > > +			if (encap_port <
> MLX5_VXLAN_PORT_RANGE_MIN
> > > > > ||
> > > > > > +			    encap_port >
> MLX5_VXLAN_PORT_RANGE_MAX)
> > > > > > +				encap_port =
> > > > > MLX5_VXLAN_PORT_RANGE_MIN;
> > > > > > +			/* Check whether UDP port is in already in
> use. */
> > > > > > +			vtep = NULL;
> > > > > > +			LIST_FOREACH(vlst, &vtep_list_vxlan, next) {
> > > > > > +				if (vlst->port == encap_port) {
> > > > > > +					vtep = vlst;
> > > > > > +					break;
> > > > > > +				}
> > > > > > +			}
> > > > >
> > > > > If you want to find out an empty port number, you can use
> > > > > rte_bitmap instead of repeating searching the entire list for
> > > > > all possible port
> > > numbers.
> > > >
> > > > We do not expect too many VXLAN devices have been created. bitmap.
> > >
> > > +1, valid point.
> > >
> > > > > > +			if (vtep) {
> > > > > > +				vtep = NULL;
> > > > > > +				continue;
> > > > > > +			}
> > > > > > +			vtep = flow_tcf_create_iface(tcf, ifouter,
> > > > > > +						     encap_port,
> error);
> > > > > > +			if (vtep) {
> > > > > > +				LIST_INSERT_HEAD(&vtep_list_vxlan,
> vtep,
> > > > > next);
> > > > > > +				break;
> > > > > > +			}
> > > > > > +			if (rte_errno != EEXIST)
> > > > > > +				break;
> > > > > > +		}
> > > > > > +	}
> > > > > > +	if (!vtep)
> > > > > > +		return 0;
> > > > > > +	vtep->refcnt++;
> > > > > > +	assert(vtep->ifindex);
> > > > > > +	return vtep->ifindex;
> > > > >
> > > > > Please refactor this func according to what I suggested for
> > > > > flow_tcf_decap_vtep_create() and flow_tcf_delete_iface().
> > > > >
> > > > > > +}
> > > > > > +
> > > > > > +/**
> > > > > > + * Creates target interface index for tunneling of any type.
> > > > > > + *
> > > > > > + * @param[in] tcf
> > > > > > + *   Context object initialized by mlx5_flow_tcf_context_create().
> > > > > > + * @param[in] ifouter
> > > > > > + *   Network interface index to attach VXLAN encap device to.
> > > > > > + * @param[in] dev_flow
> > > > > > + *   Flow tcf object with tunnel structure pointer set.
> > > > > > + * @param[out] error
> > > > > > + *   Perform verbose error reporting if not NULL.
> > > > > > + * @return
> > > > > > + *   Interface index on success, zero otherwise and rte_errno is set.
> > > > >
> > > > >  *   Interface index on success, a negative errno value otherwise and
> > > > >  *   rte_errno is set.
> > > > >
> > > > > > + */
> > > > > > +static unsigned int
> > > > > > +flow_tcf_tunnel_vtep_create(struct mlx5_flow_tcf_context *tcf,
> > > > > > +			    unsigned int ifouter,
> > > > > > +			    struct mlx5_flow *dev_flow,
> > > > > > +			    struct rte_flow_error *error) {
> > > > > > +	unsigned int ret;
> > > > > > +
> > > > > > +	assert(dev_flow->tcf.tunnel);
> > > > > > +	pthread_mutex_lock(&vtep_list_mutex);
> > > > > > +	switch (dev_flow->tcf.tunnel->type) {
> > > > > > +	case MLX5_FLOW_TCF_TUNACT_VXLAN_ENCAP:
> > > > > > +		ret = flow_tcf_encap_vtep_create(tcf, ifouter,
> > > > > > +						 dev_flow, error);
> > > > > > +		break;
> > > > > > +	case MLX5_FLOW_TCF_TUNACT_VXLAN_DECAP:
> > > > > > +		ret = flow_tcf_decap_vtep_create(tcf, dev_flow,
> error);
> > > > > > +		break;
> > > > > > +	default:
> > > > > > +		rte_flow_error_set(error, ENOTSUP,
> > > > > > +
> 	RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
> > > > > NULL,
> > > > > > +				"unsupported tunnel type");
> > > > > > +		ret = 0;
> > > > > > +		break;
> > > > > > +	}
> > > > > > +	pthread_mutex_unlock(&vtep_list_mutex);
> > > > > > +	return ret;
> > > > > > +}
> > > > > > +
> > > > > > +/**
> > > > > > + * Deletes tunneling interface by UDP port.
> > > > > > + *
> > > > > > + * @param[in] tcf
> > > > > > + *   Context object initialized by mlx5_flow_tcf_context_create().
> > > > > > + * @param[in] ifindex
> > > > > > + *   Network interface index of VXLAN device.
> > > > > > + * @param[in] dev_flow
> > > > > > + *   Flow tcf object with tunnel structure pointer set.
> > > > > > + */
> > > > > > +static void
> > > > > > +flow_tcf_tunnel_vtep_delete(struct mlx5_flow_tcf_context *tcf,
> > > > > > +			    unsigned int ifindex,
> > > > > > +			    struct mlx5_flow *dev_flow) {
> > > > > > +	struct mlx5_flow_tcf_vtep *vtep, *vlst;
> > > > > > +
> > > > > > +	assert(dev_flow->tcf.tunnel);
> > > > > > +	pthread_mutex_lock(&vtep_list_mutex);
> > > > > > +	vtep = NULL;
> > > > > > +	LIST_FOREACH(vlst, &vtep_list_vxlan, next) {
> > > > > > +		if (vlst->ifindex == ifindex) {
> > > > > > +			vtep = vlst;
> > > > > > +			break;
> > > > > > +		}
> > > > > > +	}
> > > > >
> > > > > It is weird. You just can have vtep pointer in the
> > > > > dev_flow->tcf.tunnel instead of ifindex_tun which is same as
> > > > > vtep->ifindex like the assertion below. Then, this lookup can be
> skipped.
> > > >
> > > > OK. Good optimization.
> > > >
> > > > >
> > > > > > +	if (!vtep) {
> > > > > > +		DRV_LOG(WARNING, "No VTEP device found in the
> list");
> > > > > > +		goto exit;
> > > > > > +	}
> > > > > > +	switch (dev_flow->tcf.tunnel->type) {
> > > > > > +	case MLX5_FLOW_TCF_TUNACT_VXLAN_DECAP:
> > > > > > +		break;
> > > > > > +	case MLX5_FLOW_TCF_TUNACT_VXLAN_ENCAP:
> > > > > > +/*
> > > > > > + * TODO: Remove the encap ancillary rules first.
> > > > > > + * flow_tcf_encap_neigh(tcf, vtep, dev_flow, false, NULL);
> > > > > > + * flow_tcf_encap_local(tcf, vtep, dev_flow, false, NULL);
> > > > > > +*/
> > > > >
> > > > > Is it a personal note? Please remove.
> > > > OK.
> > > >
> > > > >
> > > > > > +		break;
> > > > > > +	default:
> > > > > > +		assert(false);
> > > > > > +		DRV_LOG(WARNING, "Unsupported tunnel type");
> > > > > > +		break;
> > > > > > +	}
> > > > > > +	assert(dev_flow->tcf.tunnel->ifindex_tun == vtep->ifindex);
> > > > > > +	assert(vtep->refcnt);
> > > > > > +	if (!vtep->refcnt || !--vtep->refcnt) {
> > > > > > +		LIST_REMOVE(vtep, next);
> > > > > > +		flow_tcf_delete_iface(tcf, vtep);
> > > > > > +	}
> > > > > > +exit:
> > > > > > +	pthread_mutex_unlock(&vtep_list_mutex);
> > > > > > +}
> > > > > > +
> > > > > >  /**
> > > > > >   * Apply flow to E-Switch by sending Netlink message.
> > > > > >   *
> > > > > > @@ -3461,18 +3887,61 @@ struct pedit_parser {
> > > > > >  	       struct rte_flow_error *error)  {
> > > > > >  	struct priv *priv = dev->data->dev_private;
> > > > > > -	struct mlx5_flow_tcf_context *nl = priv->tcf_context;
> > > > > > +	struct mlx5_flow_tcf_context *tcf = priv->tcf_context;
> > > > > >  	struct mlx5_flow *dev_flow;
> > > > > >  	struct nlmsghdr *nlh;
> > > > > > +	int ret;
> > > > > >
> > > > > >  	dev_flow = LIST_FIRST(&flow->dev_flows);
> > > > > >  	/* E-Switch flow can't be expanded. */
> > > > > >  	assert(!LIST_NEXT(dev_flow, next));
> > > > > > +	if (dev_flow->tcf.applied)
> > > > > > +		return 0;
> > > > > >  	nlh = dev_flow->tcf.nlh;
> > > > > >  	nlh->nlmsg_type = RTM_NEWTFILTER;
> > > > > >  	nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE |
> > > > > NLM_F_EXCL;
> > > > > > -	if (!flow_tcf_nl_ack(nl, nlh, 0, NULL, NULL))
> > > > > > +	if (dev_flow->tcf.tunnel) {
> > > > > > +		/*
> > > > > > +		 * Replace the interface index, target for
> > > > > > +		 * encapsulation, source for decapsulation.
> > > > > > +		 */
> > > > > > +		assert(!dev_flow->tcf.tunnel->ifindex_tun);
> > > > > > +		assert(dev_flow->tcf.tunnel->ifindex_ptr);
> > > > > > +		/* Create actual VTEP device when rule is being
> applied. */
> > > > > > +		dev_flow->tcf.tunnel->ifindex_tun
> > > > > > +			= flow_tcf_tunnel_vtep_create(tcf,
> > > > > > +					*dev_flow->tcf.tunnel-
> >ifindex_ptr,
> > > > > > +					dev_flow, error);
> > > > > > +			DRV_LOG(INFO, "Replace ifindex: %d->%d",
> > > > > > +				dev_flow->tcf.tunnel->ifindex_tun,
> > > > > > +				*dev_flow->tcf.tunnel->ifindex_ptr);
> > > > > > +		if (!dev_flow->tcf.tunnel->ifindex_tun)
> > > > > > +			return -rte_errno;
> > > > > > +		dev_flow->tcf.tunnel->ifindex_org
> > > > > > +			= *dev_flow->tcf.tunnel->ifindex_ptr;
> > > > > > +		*dev_flow->tcf.tunnel->ifindex_ptr
> > > > > > +			= dev_flow->tcf.tunnel->ifindex_tun;
> > > > > > +	}
> > > > > > +	ret = flow_tcf_nl_ack(tcf, nlh, 0, NULL, NULL);
> > > > > > +	if (dev_flow->tcf.tunnel) {
> > > > > > +		DRV_LOG(INFO, "Restore ifindex: %d->%d",
> > > > > > +				dev_flow->tcf.tunnel->ifindex_org,
> > > > > > +				*dev_flow->tcf.tunnel->ifindex_ptr);
> > > > > > +		*dev_flow->tcf.tunnel->ifindex_ptr
> > > > > > +			= dev_flow->tcf.tunnel->ifindex_org;
> > > > > > +		dev_flow->tcf.tunnel->ifindex_org = 0;
> > > > >
> > > > > ifindex_org looks a temporary storage in this code. And this
> > > > > kind of hassle
> > > > > (replace/restore) is there because you took the ifindex from the
> > > > > netlink message. Why don't you have just
> > > > >
> > > > > struct mlx5_flow_tcf_tunnel_hdr {
> > > > > 	uint32_t type; /**< Tunnel action type. */
> > > > > 	unsigned int ifindex; /**< Original dst/src interface */
> > > > > 	struct mlx5_flow_tcf_vtep *vtep; /**< Tunnel endpoint device. */
> > > > > 	unsigned int *nlmsg_ifindex_ptr; /**< ifindex ptr in Netlink message.
> > > > > */ };
> > > > >
> > > > > and don't change ifindex?
> > > >
> > > > I propose to use the local variable for ifindex_org and do not
> > > > keep it in structure. *ifindex_ptr will keep.
> > >
> > > Well, you still have to restore the ifindex whenever sending the nl
> > > msg. Most of all, ifindex_ptr in nl msg isn't a right place to store the
> ifindex.
> > It is stored there for rules w/o tunnels. It is its "native" place, Id
> > prefer not to create some new location to store the original index and save
> some space.
> > We have to swap indices only if rule has requested the tunneling.  We
> > can not
> 
> No no. At this point, flow is already created to be tunneled one. What do you
> mean by 'rules w/o tunnels' or 'only if rule has requested the tunneling'??

I mean the code handles all kind of rules - with tunnel and w/o tunnels.
The same code prepares the NL message for both rule types.

> It has already been created as a vxlan tunnel rule. It won't be changed. The
> nlmsg is supposed to have vtep ifindex but translation didn't know it and
> stored the outer iface temporarily to get it replaced by vtep ifindex. It never
> be a 'native'/'original' place to store it.

I mean, if rule does not request the tunneling action - it just keeps the
unchanged ifindex within Netlink message. If there is the tunneling - we replace
this index with some value depending on this ifindex.  We cannot replace
ifindex permanently at rule translation once, because VTEPs are created 
dynamically and VTEP ifindex can be different at the rule applying time.
So, we need to keep the original ifindex and create VTEP depending on it every
time rule is being applied.

> In which case the nl msg can be sent
> with the 'original' ifindex? Any specific example? No.
> 
> > set tunnel index permanently, because rule can be
> > applied/removed/reapplied and other new VXLAN device with new index
> >can be recreated.
> 
> Every time it is applied, it will get the vtep and overwrite vtep ifindex in the nl
> msg.

Yes. We should overwrite this field anyway, and every time at rule applying.
Because vtep ifindex can be different. And we need to keep the original ifindex
(for example to dynamically  create VTEP attached to it). Do you propose to keep
ifindex_org field?  Now, as I can see we have to keep ifindex_ptr field only.

> 
> > > have vtep ifindex but it just temporarily keeps the device ifindex
> > > until vtep is created/found.
> 
> Thanks,
> Yongseok